Fixed imagery rendering issues. Robot position in Pixhawk3DWidget is now derived from the global pose (lat/lon/alt) instead of the local pose.

corrected a compile warning in Wayppoint.cc, made adaptions to Freenect for the current revision of the code (update libfreenect repository!), commented out pixhawk poi mavlink code - needs fixing

Still need to add uas connections. New osgwidget inherits from
qgraphicsview to expose more functionality to qt. Map3d.ui contains
the graphics view and some buttons. Currently runs yahoo_heightfield
by default. Make sure you run qgroundcontrol fromt the top dir or
it will seg fault, :-). I'll add some error handling soon.

Added command to select target position for robot - command can be accessed via a right-click in the 3D View perspective --Lionel